1. Field of the Invention
The present invention generally relates to an apparatus and a method for transmitting/receiving signal in a communication system, and in particular, to an apparatus and a method for transmitting/receiving signal in a communication system using a non-binary Low Density Parity Check (LDPC) code.
2. Description of the Related Art
Next-generation communication systems have evolved from a packet service communication system for transmitting burst packet data to a plurality of Mobile Stations (MSs), with the packet service communication system being suitable for mass data transmission. Further, next-generation communication systems are considering an LDPC code, together with a turbo code, as a channel code. The LDPC code is known to have an excellent performance gain at high-speed data transmission, and advantageously enhances data transmission reliability by effectively correcting an error due to noise occurring in a transmission channel. Examples of next-generation communication systems considering the use of the LDPC code include the Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system, the IEEE 802.1n communication system, etc.
Reference will now be made to a signal transmission apparatus in a common communication system using an LDPC code.
Referring to FIG. 1, a conventional signal transmission apparatus includes an encoder 111, a modulator 113 and a transmitter 115. If an information vector s to be transmitted occurs in the signal transmission apparatus, the information vector s is delivered to the encoder 111. The encoder 111 generates a codeword vector c, that is, an LDPC codeword by encoding the information vector s in an encoding scheme, and then outputs the generated codeword vector c to the modulator 113. The encoding scheme corresponds to an LDPC encoding scheme. The modulator 113 generates a modulation vector m by modulating the codeword vector c in a modulation scheme, and then outputs the generated modulation vector m to the transmitter 115. The transmitter 115 inputs therein the modulation vector m output from the modulator 113, executes transmission signal processing for the input modulation vector m, and then transmits the processed modulation vector m to a signal reception apparatus through an antenna.
Now, reference will be made to a signal reception apparatus in a common communication system using an LDPC code.
Referring to FIG. 2, a conventional signal reception apparatus includes a receiver 211, a demodulator 213 and a decoder 215. A signal transmitted by a signal transmission apparatus is received through an antenna of the signal reception apparatus, and the received signal is delivered to the receiver 211. The receiver 211 executes reception signal processing for the received signal to thereby generate a reception vector r, and then outputs the processed and generated reception vector r to the demodulator 213. The demodulator 213 inputs therein the reception vector r output from :the receiver 211, generates a demodulation vector x by demodulating the input reception vector r in a demodulation scheme corresponding to a modulation scheme applied to a modulator of the signal transmission apparatus, that is, the modulator 113, and then outputs the generated demodulation vector x to the decoder 215. The decoder 215 inputs therein the demodulation vector x output from the demodulator 213, decodes the input demodulation vector x in a decoding scheme corresponding to an encoding scheme applied to an encoder of the signal transmission apparatus, that is, the encoder 111, and then outputs the decoded demodulation vector x into a finally restored information vector ŝ. The decoding scheme, that is, an LDPC scheme, is a scheme using an iterative decoding process based on a sum-product process.
Meanwhile, a binary LDPC code is a code defined by a parity check matrix in which most elements have a value of 0, but a small minority of other elements have a non-zero value, for example, a value of 1. So, all elements of the parity check matrix of the binary LDPC code have one of a value of 0 or a non-zero value.
On the other hand, all elements of a parity check matrix of the non-binary LDPC code are elements on Galois Field (GF)(q). Here, “q” in GF(q) indicates the order of a GF, and q=2p. Thus, the non-binary LDPC code is a code defined by a parity check matrix in which most elements have a value of 0, but a small minority: of other elements are non-zero elements, for example, elements on GF(q).
Using a non-binary LDPC code has only been considered in the conventional art, but there is provided no specific solution has been provided, for example, for generating a parity check matrix of a non-binary LDPC code and encoding/decoding the non-binary LDPC code, and for transmitting/receiving a signal using the non-binary LDPC code. Accordingly, there is a need for such a solution to transmit/receive a signal using a non-binary LDPC code.